Sheave mounting



Feb. 18, 1930; w. M. VENABLE SHEAVE MOUNTING Original Fild May 3. 1928 W2! iWN VENTOR ATTORNEYS Patented Feb. 18, 193d) UNETEE @ATE @LFFEQE" KNOX COMPANY,

messy 0F PITTSBURGH, PENNSYLVANIA, A CORPORATION" OF NEW SHEAVE MOUN'IIN G Application filed May 3, 1928, Serial No. 274,751. Renewed March 5, 1929.

made to overcome the difficulties above mention by making the wearing parts of very hard steel, such as manganese steel. This, however, has led-to other difficulties, such, for example, as are involved in properly fixing or keying the sheaves to the pin upon which they rotate.

Furthermore, sheaves for the purpose referred to are generally arranged in pairs, and

since they must be fitted into a rather confined space, it is necessary to bring'them very close together, which also leads to certain difficulties from the manufacturing, as well as the maintenance, standpoints.

It is the principal object of my invention to substantially overcome all of these diificulties and to provide a sheave mounting for the purpose described which is simple to manufacture and easily assembled; one which is exceedingly rugged and in which wear is reduced to a minimum; and one in which sand, grit, dirt and water or other foreign matter can be substantially excluded from the wearing parts by proper attention to the improved lubrication means which I employ.

The foregoing, together with such other objects as may appear hereinafter, or are incident to my invention, I attain by means of a construction which is illustrated in the preferred form in the accompanying drawings, wherein Fig. 1 is a vertical section through the end of the lever arm'of an excavating bucket showing my improvements applied thereto,

and

Fig. 2 is a side elevation detail of the invention.

Referring to the drawings it will be seen that the end of the lever arm A is bifurcated so as to provide the opposed supporting arms 5. In the bucket art this portion of the lever arm is known as the sheave housing, and it is generally preferred to make the housing of a single casting so that it becomes necessary to assemble the sheaves in the housing before mounting them upon their pin.

The sheave pin 6 is non-rotatably mounted in suitable openings in the hubs 7 of the illustrating a arms 5, rotation being prevented by the keeper plates 8 which fit against the flattened port ons 9 at the ends of the pin. (See particularly Fig. 2.) Mounted directly upon the pin I provide a long bushing 10 which is free.

to rotate thereon, and in the inner surface of which is a pair of lubricant channels 11.

' Upon one end of the bushing 10 I mount a sheave 12 which I firmly secure to the bushing 10 by means of the key 13.

The hub 14L of the sheave 12 is comparatively narrow, and it will be seen that. it is considerably ofiset with respect to the center 15 of the sheave score 16.

The bushing 10 projects outwardly from the inner side of the offset hub a suficient distance to have mounted thereupon a second bushing 17 which is similarly provided on its inner surface With a lubricant channel 18.

Upon this second bushing 17 is mounted a sheave 19 which has a comparatively broad hub 20 which projects outwardly somewhat beyond the edges of its score 21, as clearly shown in the drawing, particularly in the direction of the adjacent sheave 12. In fact the inner ends of the hubs'l l and 20 are designed to contact with each other.

The center 22 of the score 21 is substantially in the plane of the vertical center line of the bushing 17.

It will be seen that this arrangement of the sheaves brings the inner sides 23 of the sheave scores 16 and 21 very closely together. A great deal of the wear has taken place at this point in previous constructions because of the fact that the sheaves would wobble upon their pin. By the improvements herein described this wobbling is almost entirely prevented so that no wear takes place at the point 23.

At the'outer side of each sheave and directly in contact with the hub, I provide a disk 24 which is mounted around the pin 6 and which is kept from rotating by means of the studs 25 which project inwardly through the hubs 7 from the planes of the outer ends of the pin as shown, the studs 25 being screwed into tapped holes in the discs 2% so that they are firmly clamped to the hubs. The circumferences of the disk 24, as well as of the adjacent hubs, are very carefully machined so that some suitable packing material 26 can be placed thereover and held in position 'by the retaining rings 27. The disks 24, therefore, might be termed sealing hubs, since they co-operate with the sheave hubs to provide'the necessary smooth bearing surface for the packing 26. Where the hub 20 projects inwardly toward the offset hub 14 the circumferences are similarly carefully machined and packing material 26 and ring 27 applied thereto.

Grease is supplied to the channels 11 through the longitudinal grease passages 28 and the transverse passages 29 radiatin therefrom. Grease is supplied to the channel 18 by means of the passage 30 in the hub 20.

The whole device is assembled as follows: The first step is to slip the inner sand sealing ring 27 with its packing 26 over the hub of the sheave 12,which is keyed to the bushing 10. Then the other sheave with its bushing 17 is placed upon the extended end of the bushing 10 so that the machined portion of its hub will fit under the sand sealing ring 27 and the packing 26. The sheaves, of course,

are resting on their flanges-on a level table,

and then one of the disks 24; is put in place, together with the respective rings 27 and packing 26. The other disk 24: immediately follows with its ring and packing and the entire assembly is inserted in the proper position in the lever arm housing, whereupon the sheave pin 6 may be pushed through and fastened in position by the keeper plates8 and studs 25.

In some instances itis desirable to make the discs or sealing hubs 24: integral with the hubs 7, in which case, as well as sometimes, for the sake of convenience, where the illustrated construction is utilized, the rings 27 are made sectional or in the form of flexible bands. With such an arrangement the rings which lie adjacent to the hubs 7 may be clamped around the packing 26 after the sheaves are in place in the housing instead of before.

The grease passages are completely filled with grease, the grease being forced in under pressure until it begins to pass out beneath the sealing rings 27. Of course, in service, the ends of the grease passages are-suitably plugged. By maintaining a proper supply of grease it is always possible to prevent almost entirely the entry of any grit or water to the bearing surfaces inside of the sheaves, as well as to the faces of the disks 24: against which the hubs of the sheaves rotate.

It will be seen that the foregoing arrangement is very simple to manufacture and easily assembled. The sheave 12 can be very firmly keyed to the bushing 10 because it is not necessary to accomplish this keying after the sheave and pin h'avebeen inserted in the housing, as was necessary in constructions heretofore in use.

The sheaves have an exceedingly long hearing on the pin 6 through the medium of the long bushing'lO, and the sheave 19 has a very large bearing area on the bushing 17 with the center 22 of its sheave score located substantially in the middle of the bushing 17. It will also be noted that the sheaves are so constructed and arranged as to bring the mid point between the centers 15 and 22 of the scores (around which the operating cables run) substantially in the plane of the vertical center line of the long-bushing 10.

The Whole structure, therefore, is well balanced and rugged, and since the sand sealing means provided very effectually excludes all grit and dirt, renewals are necessary only at much more infrequent intervals than heretofore required.

I claim 2-- 1. A sheave mounting comprising, in combination, a bifurcated support, a pin nonrotatively c rried in said support, a pair of sheaves,; a bushing keyed to one sheave and extended to one side thereof "to serve as a mounting forthe other sheave, a disc or sealing hub at the outer face of each sheave, and

a sealing ring over-the joint'between each sealing hub and the adjacent face of the re spective sheave.

2. A sheave mounting comprising, in combination a bifurcated support, a pin nonrotatively carried in said support, a pair of sheaves, a bushing keyed to one sheave and extendedto one side thereof to serve as a mounting for the other sheave, a disc or sealing hub at the outer face of each sheave, and a sealing ring over the joint between each sealing hub and the adjacent face of tie respective sheave and over the joint between the adjacent faces of the sheaves.

3. A sheave mounting comprising, in combination, a pin, a bushing thereon, a sheave keyed to one end of said bushing, a second bushing on the other end of said first bushing, and a sheave on said second bushing with the center'of its score substantially in the plane'of the center line of its bushing, the plane of the center line between the scores of said sheaves passing substantially through the middle of said first bushing.

4. A. sheave mounting comprising, in combination, a sheave having a large h-ub'whi'ch extends outwardly beyond the plane of the sheave score on each side, a second sheave having a relatively narrow hub offset with respect to the plane of the sheave score, a bushing upon which said second sheave is key-ed, said bushing extending into the hub of the first sheave, and a bushing on said extension upon which the first sheave is mounted, said bushing and the hub of the first sheave extending inwardly toward the offset hub of the second sheave beneath the flange of its score, whereby the center of the score of the first sheave is substantially in the plane of the center line of its bushing,

and the plane of the center line of said first bushing lies substantially midway between the score centers.

5. A sheave mounting comprising, in combination, a bifurcated support, a pin nonrotatively carried in said support, a bushing thereon, a sheave keyed to one end of said bushing, a second bushing on the other end of said first'bushing, a second sheave on said second bushing, a sealing hub at the outer face of each sheave, and a sealing ring over the joint between each sealing hub and the adjacent face of the respective sheave and over the joint between the adjacent faces of the sheaves.

6. A sheave mounting comprising in combination, a bifurcated support, a pin nonrotatively carried in said support, a bushing thereon, a sheave keyed to one end of said bushing, a second bushing on the other end of said first bushing, a second sheave on said second bushing, a sealing hub at the outer face of each sheave, and a sealing ring over the joint between each sealing hub and the adjacent face of the respective sheave.

7 A sheave mounting comprising, in combination, a bifurcated support,a pin nonrotatively carried in said support, a bushing thereon, a sheave keyed to one end of said bushing a second bushing on the other end of said first bushing, a second sheave-on said second bushing, a sealing hub at the outer face of each sheave, a sealing ring over the joint between each sealing hub and the adjacent face of the respective sheave andeover the joint between the adjacent faces of the sheaves, a passage in the pin for lubricating said first bushing and a passage in said second sheave for lubricating said second bushing.

8. A sheave mounting comprising, in combination, a bifurcated support, a pin nonrotatively carried in said support, a bushing thereon, a sheave keyed to one end of said bushing, a second bushing on the other end of said first bushing, a second sheave on said second bushing, a sealing hub at the outer face of each sheave, a sealing ring over the joint between each sealing hub and the adjacent face of the respective sheave and over the joint betweenthe adjacent faces of the sheaves, and a passage in said pin through which lubricant can be forced to wearing surfaces ancl out past said sealing rings.

9. In a sheave mounting, the combination of spaced supports having opposed openings for supporting a sheave pin, a sheave pin mounted in said openings and insertible and removable without disturbance of said supports, a sheave adapted to be mounted between said supports on said pin upon insertion of the latter, a sealing disc between the sheave and a support, and holding means cooperating with said support for preventing rotation of said sealing disc.

10. In a sheave mounting, the combination of spaced supports having opposed openings for supporting a sheave pin, a sheave pin mounted in said openings and insertible and removable without disturbance of said supports, a sheave adapted to be mounted between said supports on said pin upon insertion of the latter, a sealing disc between the sheave and a support, holding means cooperating with said support for preventing rotation of said sealing disc, and packing for sealing the joint between said disc and said sheave.

In testimony whereof I have hereunto signed my name.

IVILLIAM MAYO VENABLE. 

